string or procedure; name of a color scheme or a procedure that produces a color structure

schemeargs

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additional required arguments or keyword options for the given color scheme

The colorscheme Option

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The colorscheme option allows you to apply a color scheme to a plot surface or set of points created by a plot command. Note that not all plot commands support this option.

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In the first calling sequence, the colorscheme option takes a list of colors and applies the "zgradient" color scheme as described below. The colors may be specified in any of the forms described on the plot/color help page.

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In the second calling sequence, scheme is the name of a predefined color scheme, such as "zgradient", or a custom procedure. The parameter schemeargs is a sequence of arguments that is passed to the procedure implementing the color scheme.

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Note that coloring 3-D surfaces based on and values only can be done without using the colorscheme option. See the plot3d/colorfunc help page for more information.

The "zgradient" Color Scheme

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The "zgradient" color scheme is the default scheme. With a 3-D plot created by commands such as plot3d, it colors the surface based on the value. With 2-D plots such as ones created by the plots:-densityplot command, it colors the surface according to the function value associated with a given 2-D location.

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The "zgradient" color scheme requires a list of colors. which are distributed evenly over the surface. For example, if the list were ["Blue", "Green", "Red"], then the parts of the surface associated with the lowest values would be colored blue and those with the highest values would be colored red. The lower half of the values would change gradually from blue to green, and those in the exact middle would be colored green.

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The proportions of the colors in the list can be specified with the markers=mlist option, where mlist is a list of exactly increasing values starting with 0.0 and ending with 1.0. For example, if the color list ["Blue", "Green", "Red"] were given along with the markers=[0.0, 0.7, 1.0] option, then the lower 70% of the values would change from blue to green, and the upper 30% from green to red.

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By default, the RGB color space is used. You can use the colorspace="HSV" option to specify an HSV color space.

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If you wish to use either the markers or colorspace option, then you must use the second calling sequence, where the "zgradient" name and the argument list are provided explicitly.

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Normally, at least two colors are expected. If you provide an empty color list, then a black-and-white coloring is used. If you provide only one color, then that color is combined with black and white. In either case, the markers option is ignored.

Custom Color Schemes

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The second calling sequence allows you to write a custom color scheme. This feature is recommended only for experienced Maple programmers familiar with the internal plot structure as described on the plot/structure help page.

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The argument scheme must be a procedure that accepts as its first argument any of the plot structures (e.g. MESH, GRID, POINTS) to which you will apply the color scheme. It must return a valid COLOR data structure for that plot structure. It is important to ensure that the number of colors defined by the COLOR structure matches the number of colors needed by the plot structure.

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The remaining arguments in the sequence schemeargs are passed to procedure scheme. For example, if scheme requires a list of two colors and an integer, then these must be included in schemeargs when the colorscheme option is used. The procedure scheme can also be defined so it accepts keyword options. See the Argument Processing help page for more information.